is bigger than the city of philadelphia, detroit or denver. more than 1,000 firefighters are attacking the blaze, but for now, losing the battle. conditions are grueling, teams are fatigued. days are long. this hotshot crew from salt lake city has been on the front lines for 16 hours. their work here is backbreaking. their packs are full of gear, weighing over 40 pounds. the beaver creek fire may be the most dangerous blaze in the country, but it's not the only inferno threatening homes. from california to colorado, 34 major wildfires are scorching the west, the region a tinderbox, a perfect recipe for fire. >> three things affect how a wildfire burns, weather, the topography and the fuels. so, in this case, all the factors are against us. >> reporter: tonight in idaho, against the odds, firefighters battle an unrelenting blaze, one that shows little sign of slowing down. as this fire chews through forest land, crews are making progress, the blaze is 9% contained and despite the massive size of this fire, lester, only one home has been destroyed. >> miguel almaguer tonight. thank you.